Management Drug Eruption

Drug eruptions can mimic a wide range of dermatoses. The morphologies are myriad and include morbilliform (see the image below), urticarial, papulosquamous, pustular, and bullous. Medications can also cause pruritus and dysesthesia without an obvious eruption. A drug-induced reaction should be considered in any patient who is taking medications and who suddenly develops a symmetric cutaneous eruption.The history :

Use of multiple courses of therapy and prolonged administration (risk of allergic sensitization)

Any improvement after drug withdrawal and any reaction with readministration

Diagnosis With mild asymptomatic eruptions, the history and physical examination are often sufficient for diagnosis; with severe or persistent eruptions, further diagnostic testing may be required, as follows:

Biopsy

Complete blood count (CBC) with differential

Serum chemistry studies (especially for electrolyte balance and indices of renal or hepatic function in patients with severe reactions)

The ultimate goal is to identify and discontinue the offending medication if possible

Patients can sometimes continue to be treated through morbilliform eruptions; nevertheless, all patients with severe morbilliform eruptions should be monitored for mucous membrane lesions, blistering, and skin sloughing

TEN is best managed in a burn unit, and intravenous immunoglobulin (IVIG) may improve outcomes [2, 3, 4]

Hypersensitivity syndrome may have to be treated with liver transplantation if the offending drug is not stopped in time; treatment with systemic corticosteroids has been advocated in the acute phase; in the chronic phase, patients may require treatment for hypothyroidism or diabetes mellitus

For most drug eruptions, full recovery without any complications is expected; however, the following should be noted:

Patients with exanthematous eruptions should expect mild desquamation as the rash resolves

Patients with hypersensitivity syndrome are at risk of becoming hypothyroid, usually within the first 4-12 weeks after the reaction; there is also a risk of diabetes

The prognosis for patients with TEN is guarded; scarring, blindness, and death are possible

Medication

Therapy for most drug eruptions is mainly supportive in nature. Morbilliform eruptions are treated with oral antihistamines and topical steroids. IVIG is currently the most common agent used to treat TEN. Cyclosporine may also have a role in the treatment of TEN. Prednisone may be used in the treatment of hypersensitivity syndrome with heart and lung involvement, severe serum sickness–like reaction, and Sweet syndrome.

Therapy for most drug eruptions is mainly supportive in nature. Morbilliform eruptions are treated with oral antihistamines and topical steroids. IVIG is currently the most common agent used to treat TEN. Cyclosporine may also have a role in the treatment of TEN. Prednisone may be used in the treatment of hypersensitivity syndrome with heart and lung involvement, severe serum sickness–like reaction, and Sweet syndrome.

Treatment of a drug eruption depends on the specific type of reaction. Therapy for exanthematous drug eruptions is supportive in nature. First-generation antihistamines are used 24 h/d. Mild topical steroids (eg, hydrocortisone, desonide) and moisturizing lotions are also used, especially during the late desquamative phase.

Patients can possibly continue to be treated through morbilliform eruptions (ie, continue medication even in patients with a rash). The eruption often resolves, especially if the individual is being treated with antihistamines. Most authorities believe that exanthematous drug eruptions are not a precursor to severe reactions, such as TEN. Nevertheless, all patients with severe morbilliform eruptions should be monitored for mucous membrane lesions, blistering, and skin sloughing.

The ultimate goal is always to discontinue the offending medication if possible. Individuals with drug eruptions are often the most ill patients taking the most medications, many of which are essential for their survival. However, all nonessential medications should be limited. Once the offending drug has been identified, it should be promptly discontinued. Knowledge of the common eruption inducing–medications may help in identifying the offending drug.

Medicine

First-generation antihistamines. These agents antagonize H1 receptors and block release of histamine. They provide symptomatic relief of pruritus and help improve eruptions.

Hydroxyzine HCl (Anxanil, Atarax, Atozine, Durrax, Vistaril). Hydroxyzine antagonizes H1 receptors in the periphery. It may suppress histamine activity in the subcortical CNS. Hydroxyzine is available as 10-, 25-, 50-, or 100-mg tablets.

Diphenhydramine HCl (Benadryl, Benylin, Diphen, AllerMax). Diphenhydramine is used for symptomatic relief of allergic symptoms caused by the release of histamine in immune reactions.

Desonide. Desonide is for inflammatory dermatoses responsive to steroids; it decreases inflammation by suppressing the migration of PMN leukocytes and reversing capillary permeability.

Prednisone (Deltasone, Orasone, Sterapred). Prednisone is an immunosuppressant for the treatment of immune disorders; it may decrease inflammation by reversing increased capillary permeability and suppressing PMN activity; it is available in 2.5-, 5-, 10-, 20-, or 50-mg tablets.

Immunoglobulins

These agents are used to treat TEN.

Intravenous immunoglobulin (Gammagard, Gamim. Intravenous immunoglobulin is a blood product prepared from the pooled plasma of healthy donors. The following features are possibly relevant to efficacy: neutralization of circulating myelin antibodies through anti-idiotypic antibodies; down-regulation of proinflammatory cytokines, including IFN-gamma; blockade of Fc receptors on macrophages; suppression of inducer T and B cells and augmentation of T-suppressor cells; blockade of complement cascade; promotion of remyelination; and 10% increase in CSF IgG.